Strain clamp



1961 A. D. LANTZ ET AL 2,997,764

STRAIN CLAMP Filed April 25, 1957 INVENTORS ALPHA D. LA/VTZ BY ROBERT WHARMO/V m um ATTORNEY 2,997,764 STRAIN CLAMP Alpha D. Lantz, Barberton,and Robert W. Harmon,

Doyiestown, Ohio, assignors to The Ohio Brass Company, Mansfield, Ohio,a corporation of New Jersey Filed Apr. 25, 1957, Ser. No. 655,063 8Claims. (Cl. 24-135) This invention relates to cableclamps and, moreparticularly, to strain or deadened clamps for transmission lineconductors.

The principal object of the invention is to facilitate in stallation ofcable clamps in transmission lines when the conductors thereof areenergized.

Another object of the invention is to facilitate the installation ofcable clamps generally.

Still another object of the invention is to provide a multiple partstrain clamp which is simple and economical to manufacture, whileproviding functions in the clamp not heretofore provided in the cableclamps of the prior art.

In the art pertaining to cable clamps, such as are utilized in electricpower transmission and distribution systems for deadening lineconductors and cables, it is known to provide a strain clamp in whichthe seat or cable receiving groove of the clamp is formed arcuatelyalong a curve of progressively decreasing radius for providing anincreasing snubbing action. The cable is disposed along a path in whichthe line of the free end of the cable crosses the line of the bight ofthe cable and suitable clamping means are provided for securing the freeend of the cable to the body of the clamp.

A clamp of the type referred to above is described in US. Patent2,031,236 to J. J. Taylor, while a modified form of the clamp is shownin U.S. Patent 2,059,413 also to J. J. Taylor.

While such strain clamps are particularly adapted for their intendedpurpose and have been widely accepted and utilized in the electric powerline art, nonetheless, a need has existed for many years for a strainclamp which could be readily installed in an electrically energized, orso-called hot-line. That is, it is desirable to be able to install orreplace a strain clamp in a line while the line is energized so that theutilization of the line is not interrupted. This need has never beensatisfactorily met, although some attempts have been made to providespecial tools for the installation of strain clamps of the type referredto above under hot-line conditions.

We have conceived and developed, and disclose in this application, astrain clamp which incorporates the preferred features of the strainclamps described in the patents above referred to and which is alsoparticularly adapted for hot-line work. Specifically, we provide a cableclamp of the strain type in which a keeper piece for holding theare-entrant portion of the cable is supported from the body of the clampby a pivoted arrangement. The bolt for accomplishing the clamping actionis disposed at one side of the pivot, whereas a spring, which functionsnot only as a retainer for the keeper piece, but also to move the keeperpiece to an open position when the bolt is loosened, is provided betweenthe keeper piece and the body of the clamp on the opposite side of thepivot. The strain clamp of the invention has, in addition to theadvantageous features useful for hot-line work, a simplicity ofarrangement which particularly adapts the clamp for low costmanufacture.

The invention, together with further features, objects and advantagesthereof will be more clearly understood by reference to the followingdetailed specification and claims taken in connection with the appendeddrawing, in which:

in the art pertaining to such clamps.

2 FIG. 1 is a side view of the cable clamp of the invention; 7

FIG. 2 is a section view taken in the direction 2--2 in FIG. 1; and

FIG. 3 is a section view taken in the direction 33 in FIG. 1.

The strain clamp ltl'comprises a body 11 having a cable snubbing seat 12disposed about the periphery thereof. The snubbing seat 12 is ofgenerally V-shaped cross section to accommodate cables of differentdiameters and is arranged in a spiral fashion departing from a lineapproximately tangent to the entering cable at the entrance part 13according to an exponential function, as is known The bight of the cableis wound about the body of the clamp and the free end received against alateral bearing part or clamping seat, designated generally at 14, andis held against the body by a keeper 15. The lateral bearing part 14 hasan inwardly recessed groove, indicated at 16 in FIG. 2, in order toincrease the gripping action upon the end of the cable although such anarrangement is not necessary to the practice of the invention.

The keeper 15 comprises an elongated metallic piece having a widenedouter end portion 17 with the outer end thereof directed inwardly toform a bearing surface 18 for engaging the cable. At the remaining endof the keeper, a projection 19 spaced from the end of the keeper pieceis received in a shallow recess 20 formed in the adjacent side of thecross part 21. The cross part 21 extends transversely across the memberfrom adjacent the bearing part 14 to the opposed part of the body and isformed as an integral part of the body proper.

The keeper 15 has two openings (not shown in the drawing) for receivingthe ends of a U-bolt 22 which extends about the cross part 21. Two nuts23 are threaded on the ends of the U-bolt for drawing the keeper towardthebody part and clamping the cable end between the bearing part 14 ofthe body and the face 18 of the keeper. The cross part 21 hasreinforcing web 33 and 34 integrally formed with the cross part and thebody ll, along the bearing part 14, and the U-bolt 22 extends throughopenings in the webs (not shown in the drawing).

The inner end of the keeper 15 is held by a spring clip 24 which extendsfrom about the back part of the cross part 21 outwardly and circularlyback toward the keeper and has the front end thereof received in ashallow depression 25 in the front face of the keeper. The depression 25is arranged inwardly from the projection 19 so that the clip 24 exerts aforce tending to urge the keeper 15 toward an open position. Theremaining end 26 of the clip 24 is bent at right angles to the back part27 of the clip for holding the clip on the cross piece 21. A shallowgroove, such as the groove 28, may be utilized to increase the mutualpositioning and restraining action between the clip 24+, the cross piece21 and the keeper 15.

The clip 24 is suitably formed of spring material such as piano wire, orstainless steel or phosphor bronze wire and has suflicient rigidity tohold the keeper l5 properly in position while providing the necessaryelastic force for moving the keeper to an open position. Piano wire andstainless steel are to be heat treated after the wire stock is bent tothe indicated form and piano Wire is provided with a corrosionpreventing coating by galvanizing.

The body 11 has two clevis arms 29 and 30 integrally formed therewithand extending outwardly from the sides of the body and in alignment withthe cross piece 21. A pin 31 is received in openings 32 in the clevisarms 29 and 3t) and is disposed generally along the tangential linedefined by the seat at the entrance portion 13 of the clamp.

In use, the strain clamp 10 may, for example, be connected to the usualsupport by means of a pin 31. With the nuts 23 loosened sufiiciently,the cable is then passed between the arms of the clevis and about thebody of the clamp by means of a suitable hot-line tool, such asinsulated pliers or a gripping Wrench, and held in position with the endof the cable between the bearing part 14 and the end of the keeper 15.The nuts 23 are then tightened by means of a suitably insulated socketwrench and the installation is complete.

The keeper 15 is firmly held in the proper pivotal position because ofthe particular arrangement of the clip 24, even when the clamping bolt22 is very loose. While other forms of springs may be utilized withinthe spirit of the invention, the clip herein disclosed and described isespecially useful and desirable, not only in that large springing forcesare provided, but also in the mutual restraining and positioningrelationship between the clip, the body, and the keeper made possiblethereby.

The projection 19 may, of course, be formed on the cross part 21 and therecess 20 formed on the keeper.

It will be understood that the simplicity of operation makes the strainclamp advantageously useful for all ordinary purposes and the inventionis not intended to be limited to hot-line use.

It is to be understood that the foregoing description is not intended torestrict the scope of the invention and that various rearrangements ofthe parts and modifications of the design may be resorted to. Thefollowing claims are directed to combinations of elements which embodythe invention or inventions of this application.

We claim:

1. A strain clamp for use with a cable, comprising an integral body witha snubbing seat extending about the periphery thereof from a linetangential to the cable arcuately downward and back toward the cable, alateral bearing part on the part of the body which extends back towardthe cable aligned with the bottom of the snubbing seat, two clevis armsextending from the said body on opposite sides of the snubbing seat andoppositely from the said lateral bearing part, and a cross partextending inwardly from the said lateral bearing part toward thatportion of the body adjacent the clevis arms, a keeper having a lateralbearing part at one end thereof directed toward the lateral bearing partof the body, interengaging pivot means on the keeper and cross partspaced from the opposite end of the keeper, spring means operativelyconnected to the cross part and to the keeper beyond the interengagingmeans from the said one end for elastically urging the said one end ofthe keeper away from the bearing part of the body, and screw meanspositioned adjacent the said one end of the keeper operativelyconnecting the keeper to the cross part for dravn'ng the said one end ofthe keeper toward the bearing part of the body to clamp the cablebetween the keeper and the body.

2. The invention in accordance with claim 1 in which the cross part isintegrally joined with the body away from the lateral bearing part ofthe body.

3. The invention in accordance with claim 1, in which the spring meanscomprises a clip engaged with the outward sides of the cross part and ofthe keeper beyond the pivot and for moving the keeper outward and awayfrom the body at the bearing end thereof when the screw means isloosened.

4. The invention in accordance with claim 3, in which the clip passesaround and back of the cross part at the one end thereof andcircumferentially toward the keeper and into a recess therein at theremaining end thereof for mutual restraint and positioning of the clipand the keeper.

5. A strain clamp for use with a cable, comprising a body having anarcuate snubbing seat extending about the periphery of the body portionfrom a line tangential to the cable and back toward the cable, a lateralbearing pant on the part of the body which extends back toward thecable, two clevis arms extending from the said body on opposite sides ofthe snubbing seat generally opposite the lateral bearing part of thebody and aligned with the cable, a cross part extending from the lateralbearing part to the body of the clamp adjacent the clevis arms andintegral therewith, a keeper having a lateral bearing part at one endthereof directed toward the lateral hearing part of the body,interengaging pivot means on the keeper and cross part adjacent theopposite end of the keeper and spaced therefrom, a spring memberdisposed about the cross part of the body and the said opposite end ofthe keeper and beyond the pivot means from the said one end of thekeeper for elastically urging the said one end of the keeper away fromthe bearing portion of the body, and a U-bolt disposed about the crosspart of the body and the keeper with outwardly directed ends and nutsthereon for drawing the said one end of the keeper toward the saidbearing part of the body to clamp the cable between the keeper and thebody.

6. A strain clamp for use with a cable, comprising an integral bodyportion with a snubbing seat extending about the periphery thereof froma line tangential to the cable arcuately downward, and back toward thecable to constitute a re-entrant part of the body, a lateral bearingpart of the said re-entrant part and comprising a clamping seat alignedwith the bottom of the snubbing seat, two clevis arms extending from thesaid body on opposite sides of the snubbing seat disposed oppositelyfrom the said rc-entrant part, and a cross part extending from there-entrant part to the body of the clamp adjacent the clevis arms, akeper having a lateral bearing part at one end thereof directed towardthe clamping seat, and an inward projection spaced from the opposite endthereof and engaged with the cross part to pivot thereon, a springmember disposed about the cross part and the said opposite end of thekeeper and engaged with the outward sides thereof for normally urgingthe said one end of the keeper away from the bearing portion of thebody, and a U-bolt disposed about the cross part of the body andreceived in openings in the keeper and nuts on the ends thereof forclamping the loose end of a cable between the keeper and the bearingpart of the body.

7. The invention in accordance with claim 6, the body having a recess onthe cross part with the projection of the keeper received therein forlongitudinally positioning the keeper.

8. The invention in accordance with claim 6, the said spring membercomprising a clip having a straight part engaged with the cross part onthe outward side thereof and a circumferential part With the end thereofengaged with the keeper on the outward side thereof.

9. The invention in accordance with claim 8, the keeper having adepression on the outward side thereof for receiving the said end of theclip and an inwardly directed piece on the remaining end of the clip formutually positioning and restraining the clip and keeper with respect tothe cross part.

References Cited in the file of this patent UNITED STATES PATENTS698,572 Smith Apr. 29, 1902 882,408 Mullin Nov. 17, 1908 2,031,236Taylor Feb. 18, 1936 2,043,555 Preston June 9, 1936 2,059,413 TaylorNov. 3, 1936 2,309,851 Kuhne Feb. 2, 1943 2,697,262 Olsen Dec. 21, 1954FOREIGN PATENTS 962,610 France Dec. 12, 1949

